The 5-velocities UA ≡dxA/dλ where λ is an affine parameter obey UAUA = 0 (we absorb the speed of light c here, and the gravitational constant G and Planck’s constant h elsewhere,by a choiceof unitsthat renders them all unity). With λ=s for the proper 4D time, the velocity in ordinary space (v) is related to the velocity along the axis of ordinary time (u) and the velocity along the fifth dimension (w) by v2 = u2 +w2. This implies super-luminal speeds; but the